From 58503ee01d64f5958172bd26511ebb7c67d6129f Mon Sep 17 00:00:00 2001
From: Hein Dauven <heindauven@gmail.com>
Date: Sat, 10 Oct 2026 14:02:04 +0200
Subject: [PATCH] Add tests for the gaps found by mutation testing

Mutation testing of dusk-safe 0.4.0 found code that no test pins. Each
test below fails on the mutant it targets:

- Test that dropping a sponge wipes its output
- Test the IO-pattern call length bound
---
 src/lib.rs    | 17 +++++++++++++++++
 src/sponge.rs | 15 +++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 1f4931b..e906aa9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -281,6 +281,23 @@ mod tests {
         assert!(validate_io_pattern(&iopattern).is_err());
     }
 
+    #[test]
+    fn io_pattern_length_bound() {
+        const MAX: usize = (1 << 31) - 1;
+        assert!(
+            validate_io_pattern([Call::Absorb(MAX), Call::Squeeze(MAX)])
+                .is_ok()
+        );
+        assert!(
+            validate_io_pattern([Call::Absorb(MAX + 1), Call::Squeeze(1)])
+                .is_err()
+        );
+        assert!(
+            validate_io_pattern([Call::Absorb(1), Call::Squeeze(MAX + 1)])
+                .is_err()
+        );
+    }
+
     #[test]
     fn test_tag_input() -> Result<(), Error> {
         let domain_sep = 42;
diff --git a/src/sponge.rs b/src/sponge.rs
index db4e1f2..d57d91a 100644
--- a/src/sponge.rs
+++ b/src/sponge.rs
@@ -479,6 +479,21 @@ mod storage_tests {
         }
     }
     #[test]
+    fn drop_wipes_buffered_output() {
+        let mut sponge = Sponge::start(
+            Identity,
+            vec![Call::Absorb(1), Call::Squeeze(1), Call::Squeeze(1)],
+            0,
+        )
+        .unwrap();
+        sponge.absorb(1, [99]).unwrap();
+        sponge.squeeze(1).unwrap();
+        watch(&sponge.output[0]);
+        // A sponge dropped before `finish` still holds its output.
+        drop(sponge);
+        assert!(WIPED.get(), "buffered output must be wiped on drop");
+    }
+    #[test]
     fn allocation_failure_is_terminal() {
         for buffered in [false, true] {
             let mut sponge = Sponge::start(